To score a pot or piece of clay means to scratch hatch marks on it as part of joining clay pieces together. This is done before brushing on slurry and joining the pieces together. The process is often called "score and slip." For example, you may say, "I scored and slipped the pitcher before joining its handle to it."
Scoring to Join Pieces Together
Scoring is a key part of attaching one piece of clay to another. A common task is to attach a handle to a mug or jar, attaching a decoration to a piece, or mating coils together. Simply marrying them together by physically blending them is possible while the clay is still soft and wet. But if they aren't firmly united together, they can fall apart as they dry or are fired in the kiln. Attempting to marry them together can also deform them, which is especially a problem for more delicate handles or decorations.
Instead, you can form the pieces separately and then use the scoring and slipping technique to attach them while they are set in shape yet still wet enough to be incised, or scored. Slip is a mixture of clay and water is used to glue the join together. The piece will then be dried until it is bone dry before bisque firing.
You can buy scoring tools made especially for pottery. However, you can use just about any sharp object for scoring. A needle, pin, fork, comb, sharp pencil, or a chopstick can be used. For small objects, you can even use a toothbrush to score and slip at the same time. You simply need a tool that will incise scratches that are deep enough to take in the slip and allow the pieces to be united firmly after they have dried and been fired.
Scoring Technique for Pottery
You will need to score your main object and what you are attaching to it. You should note or mark exactly where you are going to join them together. Then use the scoring tool to make crisscross marks on each of the objects. You don't want these marks to extend past the join area, or they will be visible after drying and firing.
Once both objects are scored, the slip is applied to one or both of the scored areas and the objects are pressed together. Some potters use only water or even spit, rather than using slip composed of a combination of clay and water. Some also use a vinegar and water solution.
After attaching the two objects, clean the area to remove excess slip with a paintbrush or sponge. Care has to be taken in allowing time for the mated pieces to meld. Some people wrap it in plastic or leave it in a humid room for a day, so they mate together, and both parts are equally wet and dry. This time period allows the moisture to even out between the parts. After that, proceed with drying to bone dry before firing.